Hydroforming process



lHM171948 A. B. WELTY, JR., HAL v2,447,043

HYDROFORMING PROCESS Filed Aug. 24, 1944 e w Y fr. e 0

C Z z'ntorz W.

. f Clbborneq Patented Aug.17, 194s l d 2,447,043

UNITED STATES PATENT OFFICE HYDROFORMIN G PROCESS Albert B. Welty, Jr.,Mountainside, and Clinton H. Holder, Cranford, N. J., assignors toStandard Oil Development Company, a corporation of Delaware ApplicationAugust 24, 19444, serial Nu. 551,038

i 2 Claims. (C1. 196-53) 1 y 2 The present invention relates toimprovements eration), is used and the feed rate is 0.65 volumes in theart of reforming, and more particularly it of feed per volume ofcatalyst per h'our, it is relates to a continuous method of reformingnaphfound that the 50-100 cubic f eet of air per 'cubic thas which maybe accomplished more expedif foot of catalyst is equivalent to the airneeded tiously and cheaply than heretofore possible. 5 to burn 0.2-0.4weight per cent carbon (as coke) Hereinafter the term hydroformingrefers to based on feed. It is readily seen that if the a catalyticoperation carried out in the presence reaction period is decreased, thiscoke equivalent of a reforming catalyst, such as a sixth group of theexcess air in terms of feed stock increases oxide supported on activealumina and in the because less oil is f ed per reaction period. Forpresence of added hydrogen, the principal chemexample, decreasing thereaction period from four ical reaction being one in whichdehydrogenation hours to one hour would increase the coke equivaofhydrocarbons takes place, but is also accomlent of the excess airrequired to 0.9 to 1.8 weight panied by certain other reactions such asisomeriper cent on feed. This is very appreciable in zation,polymerization, and the like. comparison with the 0.1-0.3 actual weightper Until recently al1 catalysts used in hydroform- 15 cent cokeordinarily formed when operating to ing have been subject to oxidationand reduction. make toluene from a feed containing methylcyclo-lHydroforming is a. cyclic process, that is, the hexane. Under moresevere conditions actual catalyst is alternately used for reaction, thencoke may amount to as much as 2.0-3.0 weight regenerated. 'I'he resultis that the vcatalyst is per cent on feed, however.

oxidized during regeneration and reduced during According to our presentinvention, we employ the reaction period (actually during the purging amodified hydroforming, catalyst and are able with hydrogen-containingrecycle gas :lust precedto change hydroforming technique fundameningeach reaction period). This is evidently the tally. 8S Will appear morefully hereinafter; We

result of oxidation and reduction of the activatuse a hydroformingcatalyst containing an elkeing metal oxide. For example, in the case ofa line earth Oxide. Such 8S C610. molybdenum oxide-alumina catalyst thereaction An advantage 0f 0111 PrOceSS iS that We are able that takesplace may be represented approxito employ a uid" catalyst process ratherthan mately as follows: esetationry bllad of catalyst. which hasheretofore n use exc usively in commercial hydroform- MoOa+H2 H20+MoOz(during hYdrOfOrninS) 30 ing. As is known in iiuid catalyst technique,the and catalti. in the form of a relatively fine powder and gregeneration is mixed with the regen- MoO2+1/2O2 M003 (duringregeneration) eration gas in the regeneration zone. When us- Actuallythe reactions may be somewhat more ining the Ordinary reforming catalystin this fluid volved than shown. One result of this alternate Catalysttype 0f Operation, the catalyst is resident oxidation and reduction yisthat air is required in the reaction zone for only about five minutes.during th regeneration over and above that used Employing the 11511811catalyst, if es UOlnpiete oxiup in burning coke formed during therefgrmipg Q dation (during regeneration) and reduction (durphase. In thecase of a typical molybdenum ing purging and hydroformlng) took place inthis oxide-alumina catalyst this additional amount of type 0f OperaiiinBIS When using the longer PeriOdS air is -100 cubic feet per cubic footof vcatalyst. in the Stationary bed. the ecke equivalent 0i the' In thecase of certain chromium oxide-alumina eXCeSS air required would be fromill-22` weight catalysts tested, the excess air amounts to per centbased on the feed. Of course, this would cubic feet per cubic foot whenthe catalyst is be prohibitive and render the process entirely freshlyprepared and 40-50 after use. The mo- 45 impractical from a commercialstandpoint.' This lybdenum oxide type catalysts are generally usedsituation, however, may be alleviated Somewhat in hydroforming and weshall egniinethe remaindue to the fact that the oxidation and reductioning discussion to this kind for purposes of illusin the regenerationzone and the reforming zone, trating. The amount of air required inexcess of respectively. WOllld not be'eS complete in the uid thatrequired for burningcoke overagiven period 0 catalyst process as in thestationary bed type of time will depend on the length of cycleemoperation because of the relative shortness of the ployed. The morefrequently the catalyst is recycle. But in any event the air requiredfor oxigenerated, the more excess air will be required. dation of thecatalystitself would be very great If a typical cycle length and feedrate, 8 hours (4 and Wi11,in most cases, exceed the air required fOrhours reaction and 4 hours purgingand regen- 55 burningcoke. However,the additional air it is 3 necessary to supply to reoxidize the catalystIis not the only disadvantage of the catalyst which is subject tooxidation and reduction. When the air oxidizes the catalyst per se,about as much heat is evolved per unit of oxygen consumed as when theoxygen is used to burn the coke in the fouled catalyst duringregeneration; therefore, facilities for heat removal mustbe greatlyincreased using the ordinary reforming catalyst in the uld catalyst typeof operation.

We ha've found (as indicated previously) that the disadvantages ofapplying the iluid catalyst type of operation using sixth group oxidecatalysts can be minimized or eliminated by modifying the catalyst. Forexample, by inclusion of calcium oxide in the molybdenum oxide-aluminacatalyst in approximately 1:1 mole ratio of calcium to molybdenum, thealternate oxidation and reduction can be essentially eliminated, that isto say, during the hydroforming .operation the catalyst is not reducedand therefore it is not necessary.

to reoxidize it during regeneration. Calcium oxide can be used tostabilize not only molybdenum oxide-alumina catalyst, but it can also beused to stabilize chromium oxide-alumina catalyst or any oxide catalystwhich' is subject to oxidationreductlon, such as tungsten oxide, ironoxide, cobalt oxide, nickel oxide, manganese oxide and the like. Also,instead of using calcium oxide ior stabilization purposes, we may usethe oxides of the second group of the periodic table, generally, and inparticular oxides such as magnesium oxide, strontium oxide and bariumoxide.

Another feature of our invention involves using a spinel type compound.such as zinc aluminate or zinc spinel, as it is often called, as thecatalyst support or carrier, in place of active alumina. This feature isimportant for the zinc spinel increases the activity oi the catalyst,particularly in that the zinc spinel increases the cyclicizing action ofthe catalyst so that not only are naphthenes in a. feed converted toaromatics, but also the. parailins invariably present in the reactionzone are cyclicized and/or aromatized and converted into aromatics.Hence, using a z'inc spinel base, the overall yield of aromatica from agiven quantity of virgin naphtha is greater than where the active oxideis supported on, say, active alumina or other known supports. l

In preparing the spinel base catalyst, we may employ the techniquedisclosed in the application of Kenneth K. Kearby, Serial No. 521,663,filed February 9, 1944, which is now abandoned. Thus one good way toproceed, disclosed in said application, is as follows:

Example 1 l solution .4.-9'14 g. of c. P. zinc nitrate tilled water andmade up to a volume of 3290 cc.

- Solution B.-80 g. pure NaOH was dissolved in 4 liters of distilledwater. 800 g. of sodium aluminate was stirred in rapidly. After stirringfor two minutes, 500 cc. of a diatomaceous earth nlter aid was added.stirring was continued for onehalf minute and the suspension wasilltered on a Buchner funnel. 3290 cc. of the filtrate was used forsolution B. The resulting solution had a concentration of 101 g. A120:and 87 g. NazO per liter. On this basis, the acidity of the zinc nitrate(Solution A) was adjusted to exactly neutralize the alkali of thealumina solution.

Solutions A and B were added at equal rates over a period of 30 minutesto 10 liters of distilled water while stirring. Stirring was continuedfor 15 minutes after all of A and B had been added and the precipitatefiltered. l The precipitate was washed with 6 liters H2O, restirred in12 liters of water, filtered and washed with 6 liters H2O. Theprecipitate was dried and calcined 3 hours at 1000 F. 'I'he zincaluminate is placed in a solution of calcium nitrate in distilled watercontaining 375 grams of calcium nitrate Per liter (2.5 cc. of solutionper gm. of zinc aluminate). The mixture is stirred for four hours. 'I'he'solid material was illtered and was then dried at 250 F. Ihe driedpowder was then heated at about 750 F. until most of the nitrate hasbeen decomposed. The temperature was then increased to l250 F. andmaintained for 6 hours.

The ignited calcium-oxide containing zinc aluminate was mixed for 3hours in the ball mill with a'solution of 81.8 g. oi C. P. ammoniummolybdate dissolved in a solution of 44 cc. concentrated ammoniumhydroxide in 440 cc. H2O.

(Additional wa'r was added, suilcient to form a thick paste beforemixing.) The mixture was dried, pilled and calcined for 3 hours at 1200"F.

'Ihe foregoing example is obviously purely illustrative andany techniquefor incorporating calcium molybdate into a spinel, particularly a, zincaluminate spinel, may be us'ed. In like manner calcium chromatesupported on or impregnated into a spinel base gives a good catalyst forhydroiorming" naphthas. We have termed calcium molybdate, strontiummolybdate, calcium chromate, etc., stabilized oxides which means thatthe oxide oi' molybdenum or chromium does not undergo valency changeduring a passage through an oxidation zone and a reduction zone.Similarly, tungsten oxide in equimolecular proportion with calcium oxidemay be present.

With respect to the amount of spinel with respect to the stabilizedoxide, we use a preponderance of the spinel carrier,l i. e. over 50weight per cent up to 95 weight per cent. the balance beingsubstantially the stabilized oxide.

In the accompanying drawing, we have shown for purposes of betterillustrating our invention a flow plan depicting diagrammatically anappaatus layout in which our invention may be perormed.

Referring to the drawing in detail, powdered -ilowing powdered catalyst.A flow control valve I l is disposed at the bottom of standpipe 3.

In order to further illustrate our invention, we shall describe a methodof hydroforming a naphtha fraction to form toluene. To this end anaphtha containing at least 30% naphthenes, and preferably 60-70%,boiling within the range of from 20G-240 F. is introduced into thepresent system through line 29 and thence heated in a nredcoil2ltoatemperatureotaro1md5001". whereupon it is withdrawn through line 30and then discharged into the lower bend i2 of the standpipe 3. Hydrogenor a gas rich in hydrogen is introduced into the present system throughline 2i and heated in a separate coil 22 to a temperature of about 500F. and then discharged into line 30. In the lower bend of standpipe 3,after the vaporized naphtha has been injected, there is contained ailuidized mixture of catalyst, naphtha, hydrogen, and the gas addedthrough taps 5, the latter gas being natural gas, nitrogen, hydrogen,

recycle gas (hydrogen and hydrocarbon gases),

normally gaseous hydrocarbons from" petroleum sources, and the like, butpreferably steam is avoided. The iiuidlzed mass is discharged from thestandpipe into a reaction vessel` 35, passing through a. foraminousmember 31 which may be an ordinary screen or grid plate serving thepurpose of increasing the distribution and uniformity of flow of thefluidized mass into the main body of the reactor. The flow of gas orvapor in the reactor 35 is controlled so .that its superficialvelocityis from 1)/3-5 ft. persecond, preferably from 1% to 3 ft. persecond, whereupon there is formed within the reactor a dense, fluidizedmasshaving the cw characteristics andstatic pressure of a fluid, likewater. VThis mass may weigh -70 lbs. per cu. ft. preferably 15-40 lbs.per cu. It. It is characterized by a series of vertical and crosscurrents extending from the grid plate to an upper level designated L,with lthe net result that a thorough and complete mixing is achieved andtherefore all portions of the mass are at substantially the sametemperature. It will be noted that the naphtha was heated to only about500 F. in the heater 25 because in the type of operation described thecatalyst from hopper l is in heated condition as a result of a priorregeneration, as will subsequently appear more fully hereinafter.

The reactants pass upwardly into a disengaging chamber 40 where thesuperficial velocity of the vapors is decreased to the extent that themain bulk of the catalyst carried therein gravitates back into the spacebetween grid plate 31 and upper level L. In other words, the superficialvelocity of the vapors in disengaging chamber 40 is of the order of 1/ft. per second, or less, and at this low velocity the catalyst settlesout and descends to the lower` portion of the resuitable solid-gascontacting devices, such as centrifugal separators, electricalprecipitators, etc. to remove the catalyst which may be entrainedtherein in small amounts; that is to say, the gases exiting in line 62from disengaging space 40 may contain V2 of 1% or thereabouts, of thecatalyst,

and to remove thisn entrained catalyst the vapors are subjected to thetreatment referred to.

Referring to the drawing, it will be noted that we provide a draw-oilpipe 39 through which cat.- alyst may be withdrawn continuously from thereactor and ldischarged into a mixing means such as an injector 50 whereit is mixed with air or other oxygen-containing gas discharged into themixer 50 through line 52 to form therein a fluidized mass of spentcatalyst in oxygen-containing gas, which fiuidized mass is thenwithdrawn through line 55 and discharged into a regeneration vessel 60similar in construction to the reactor 35 and preferably disposed at asomewhat lower level. y The fiuidized spent catalyst passes upwardlythrough a screen or grid distributing plate 59 into the regenerator 60where, asin the case of the reaction vessel, the supercial velocity ofthe gas is regulated from 1-5 or 6 ft. per second, preferably 11/2 to 3ft. per second to form in the regenerator a fluidized, turbulent mass ofcatalyst ldispersed or mixed with regeneration gas of about the samedensity as the material in the reactor.

bulk of catalyst, the latter being discharged intothe regenerationvessel and the regeneration gas passing overhead through line 10. Thisregeneration gas may contain some entrained catalyst and, if so, it ispassed through dust separators, electrical precipitators, and the like,and then the gas may be passed through a waste heat boiler 15 torecover, for use in the system, at least a portion of its sensible heat,whereupon the gases are vented from the system through line 80. Theregenerated catalyst may be continuously withdrawn from the regeneratorthrough a bottom draw-oil` pipe |00 and then conveyed by any suitablemeans, such as Redler conveyor, to hopper I for reuse in the process.

As to operating conditons, the following give good results:

It willbe understood that the details of opera-- tion which we havehereinbefore set forth are purely illustrative and do not per se imposeany limitation on our invention. So far as we know we are the iirst todevise a practical method for hydroforming catalytically, using thehereinbefore described fluid catalyst process. It has been impracticalto employ this type of process heretofore due to the aforementionedinstability of the molybdenum oxide, chromium oxide, and the like, andby using the calcium or other stabilizing oxide We are enabled to passthe catalyst through the hydroforming zone and the regeneration zonewithout causing it to undergo change in valence or oxidation and/orreduction.

While vthis new class of catalysts is particularly adapted for use in a"uid catalyst type o'f operation, they may be used in the conventionaloperation, i. e., in the form -of a stationary bed or beds, with goodresults.

To recapitulate, our present invention relates primarily toreformingnaphthas using a stabilized oxide catalyst, but includes anyoperation performed on hydrocarbons involving dehydrogenation,aromatization, cyclization, etc., and where coke or carbonaceousdeposits are formed on the catalyst during the reaction, and has for itsmain purpose a saving in regeneration volume and utilities duringregeneration of the catalyst :d by burning oit the said coke," since theactive component of the catalyst during the productive reaction isstabilized against valence changeor reduction. 'I'his stabilization o1'the catalyst obviatcs' the necessity oi re-oxidizing the catalyst withits attendant saving of air and heat controlling utilities. Sinceoxidations are exothermic provisions must be made to remove heatordinarily to prevent injury to the catalyst. Hence, the saving ofregeneration volume and cooling means afford the main advantages of ourinvention, coupled of course, with the saving in time'required torecondition a fouled catalyst oi' the tyne here involved.

For simplicity sake, we have not shown separation of hydrogen from thereaction gases, and its recycling to coil 22 for further use in theprocess because this also is well knownto the art and does not form apart of the present inventon. It will be understood, of course, that allthe expedients of recycling hydrogen. solvent treating, fractionation,distillation, etc. are expedients which may be used as part of ourprocess.

What we claim is:

1. A hydroforming process which comprises establishing a fiuidized massof powdered hydroforming catalyst carried on a support, said catalystincluding a metallic oxide normally tending to be reduced by hydrogenunder the conditions of reaction, said metallic oxide being selectedfrom the class consisting of `molybdenum,'

chromium and tungsten oxides andA said metallic oxide being chemicallycombined mole for mole with calcium oxide, continuously feeding powderedcatalyst and gasiform hydrocarbons into a reaction zone containing saidiluidized mass, permitting the hydrocarbons and catalyst to contact eachother in the reaction zone in the presence of added hydrogen for asumcient period to eiIect the desired reaction, withdrawing reactionproducts, purifying and recovering the same, separately withdrawing ailuidized stream ot spent catalyst in substantially unreduced conditionbut containing carbcnaceous deposits, conveying the spent catalyst to aseparate regeneration zone, establishing Within said regeneration zone afluidized mass of catalyst, intermixed with an oxidizing regenerationgas in amount not substantially in excess of that required to burn offcarbonaceous deposits, permitting the regeneration gas to contact thecatalyst at a sufficiently elevated temperature to cause burning of thecarbonaceous deposits, separating the catalyst from the gases andrecycling a fluidized stream` of regenerated catalyst while still hot tothe re` action zone. p 2. A hydroforming process according to claim 1wherein said support comprises zinc spinel.

ALBERT B. WELTY, Jn.

CLINTON H. HOLDER.

REFERENCES CITED The following references are of record in the file ofthis patent:

. UNITED STATES PATENTS 25 Number Name Date 1,732,381 Schmidt et al.Oct. 22, 1929 2,278,223 Sturgeon Mar. 31, 1942 2,304,168 Heard Dec. 8,1942 2,311,979 Corson Feb. 23, 1943 2,341,193 Scheineman Feb. 8, 19442,344,330 Sturgeon Mar. 14, 1944 2,351,624 Mavity June 20, 19442,360,463 Arveson Oct. 17, 1944 2,367,530 Ruthru Jan. 16, 1945'2,380,035 Edson et al. July 10, 1945 2,387,989 Foster -1 Oct. 30, 19452,422,372 Smith June 17, 1947 FOREIGN PATENTS 40 Number Country Date268,774 Great Britain Mar. 28, 1927

